It is known that the stability of excavators is a function of the angular position of the upper frame (“turret”) with respect to the carriage and the weight of the hanging loads suspended from the articulated excavator arm.
The excavator arm is usually defined by a lift boom, hinged to a distal arm.
In detail, the further the plane in which the excavator arm and the longitudinal axis of the carriage are located from the mutually parallel condition, the greater the risk of the machine's tipping.
The risk grows together with the weight of the load.
At present, a pressure sensor, arranged at the piston side of the boom cylinder of the boom, is used in order to prevent the risk of tipping.
When the pressure detected by the sensor exceeds a safety threshold, a signal is emitted internally of the drive cabin, for example a sound alarm, which informs the driver of the risk of vehicle instability.
As a precaution, the cited threshold relates to the value of the maximum load that can be lifted when the turret is in the riskiest position, i.e. the position in which the excavator arm is perpendicular to the axis of the carriage.
This system has the drawback of being poorly efficient.
In fact, the operator knows that the danger signal is emitted also in conditions that are not necessarily dangerous, i.e. when the pressure detected by the sensor is critical but the plane of the arm is not perpendicular to the axis of the carriage.
In the above-described circumstance, the operator will assess the risk of proceeding to the complete lifting of the load using the well-known lift tables; this is inefficient and renders partially useless the fact that an automated safety system is provided on the vehicle.